The present invention relates to a wind-up mechanism for a tiltable umbrella, such as garden, beach, terrace and other such large umbrellas which have the ability to tilt as desired.
In particular, the present invention is directed to an improvement in umbrellas equipped with a wind-up mechanism which is mounted on the umbrella pole for opening the umbrella and then tilting same in response to the winding of respective first and second portions of the same flexible cable. Examples of such umbrella constructions can be found in U.S. Pat. Nos. 2,721,569, 3,142,307, 3,150,671 and 3,175,568. U.S. Pat. No. 2,595,697 shows an alternate type of umbrella assembly wherein two wind-up mechanisms are needed to open and tilt an umbrella.
In this single mechanism type of tiltable umbrella, a crank and gear arrangement is provided which winds a flexible cable on a cylinder. After turning the crank a number of rotations, the umbrella opens to its fully opened state. Further rotation of the crank causes compression of a 200 pound spring, which thereby permits the upper end of the umbrella to tilt in a controlled manner. In order to obtain a sufficient mechanical advantage to compress the spring, the cylinder must be of sufficiently small radius. Unfortunately, this results in an undesirable number of rotations in order to open the umbrella and present constructions require approximately 40 rotations of the crank to open the umbrella.